The present disclosure relates to a non-contact charger and a non-contact charging method of charging secondary batteries mounted on, for example, an electric propulsion vehicle (e.g., an electric vehicle, and a hybrid vehicle) via a non-contact method.
Techniques utilizing magnetic fields, electric fields, radio waves, etc., are being developed to transmit power of a non-contact charger via a non-contact method. Such non-contact power transmitting techniques do not require any wires or connectors connecting a power supplier and a power receiver. This allows users to save trouble for connection. There is a lower risk of electric leakage or electric shock when it rains.
Such a non-contact charger includes an inverter circuit, from which a current of a predetermined frequency is supplied to a transmitting coil. The transmitting coil generates a magnetic flux.
As a non-contact power transmitting method utilizing magnetic resonance generated by combining transmitting and receiving coils, a suggested technique is to detect the maximum power frequency at which the receiving coil receives maximum power so that the frequency of the power transmitted by the transmitting coil is equal to the maximum power frequency (see, e.g., Japanese Unexamined Patent Publication No. 2011-142769).